I have a normal Button and TextBox in a WPF-Window and I want a Template for the Button with a EventTrigger that listens to Button.Click and then sets a boolean-property of the TextBox. No code-behind.
Something like this:
<ControlTemplate.Triggers>
<EventTrigger SourceName="MyButton" RoutedEvent="Button.Click">
<Setter TargetName="MyTextBox" Property="Focusable" Value="False" />
</EventTrigger>
Here is a sample that sets and clears
Focusable
on a TextBox from an EventTrigger.Hopefully you can adapt this example to your situation.